# MAL-2026-6553: Malicious code in insomnia-plugin-poc-m4gester2 (npm)


- **Type:** Malicious package
- **Package:** `insomnia-plugin-poc-m4gester2` (npm)
- **Published:** 28 Jun 2026

## What is MAL-2026-6553?

MAL-2026-6553 is a malicious package in insomnia-plugin-poc-m4gester2, published on 28 Jun 2026. 

### Official description

Package ships only a package.json with no plugin code, declaring a postinstall lifecycle script that runs `echo PWNED_BY_DEEPLINK > /tmp/pwned.txt` on every `npm install`. This writes a marker file to the installer's filesystem and demonstrates arbitrary command execution at install time. The package name self-identifies as a proof-of-concept (`poc-m4gester`) and adopts the `insomnia-plugin-*` namespace despite shipping no Insomnia plugin functionality. While the current payload is a benign marker write, the postinstall is an arbitrary-shell-on-install primitive with no legitimate purpose, in a namespace-squat shell of a package.

## What should I do about MAL-2026-6553?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-6553 is a malicious package: insomnia-plugin-poc-m4gester2 (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-6553/ (Markdown: https://insights.sbomify.com/MAL-2026-6553/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6553

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6553/
Summaries are generated and may contain mistakes; the official description above is the record.